Electrically-heated steel-furnace.



J. L. DIXON.

ELECTRICALLY HEATED STEE L FURNACE. APPLICATION FILED 001:14. 1916.

1,214,763. Patented Feb. 6,1917;

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- esnecmily 4 1 tncel urciurna-ces LAWEGN EIXGE', GE DETROIT, MICHIGAN.

ELFSTJTEKJALLY-HEATED STEEL-FURNACE.

Specification of Letters ;Patent.

Patented Feb. 6, 1917.

Application sctcber 14, 1916. Serial No. 125,558.

To all wiwmmay concern: Be it known Jesse DIXGN, o subjec t GreatBritain, residcounty of VJ yne and State of Michigan, have inventedcertain new usezul improvements in Electrically-Elected steel-Furnaces;I do hereby declare the iiol owing to be a full, clear, and exactdescription of the invention, such others sgilled in the art tonppcitsins to make end use the invention has particular refelectricalmetallurgical furnaces, cl furnaces, of the type which supply the heatare formed by currents passing from and to movable electrodes suiteccispended above the bath or ma er-is act a npcn. in other Words hasreference to elec wherein he crucible is not included within the elmeans electrodes, eiliner sutozna simple and certain.

'ruct furnaces two phase four movable to be treated "sioodl, it ishighly deform heating; ccndingths of the four arcs equsl arrnngementeach in of electrodes oelongs virtually to en 'ndependent single hosecircuit, since all possible.

be current passing through either member f either its way hucic throughhe other member ofthe same pain In conequence, indicator of lmngcs incurrenttrengtli associated with either crlootli members of :1 pair wouldnot alone give a sig nificsnt inv cation, since any change of currentshown is due to a change in the sum of the lengths of the pair of arcsand not to any change in either arc clone. Such c sys tern musttherefore be furnished with both nmmeter and. voltmeter apparatus,whether hand or regulation. T 1? ome ai n oi re s man which may beconsidered as a special case analogous to a delta connection. I then soconnect the four movable electrodes that they appear at the four cornersof the square in the vector dingram.

In the drawings, Figure 1 is a diagram showing a .preferred connectionfor carryout this general plum-and Fig. 2 is a vector .diay'ramcorresponding to the connections shown in Fig. 1.

In the particular embodiment of my invention herein illustrated. threephase current is supplied on the mains 10, 11 and 12, to the primaries13 and l-l of two Scottconnccted transformers The secondary associatedwith the primar} winding 13 is divided into two equal portions 15 and16, and the secondary associated with the prinmry 1% is similarlydivided into sections 1? and 18. As shown in Fig. l. the left handterminal of the winding 15 is connected. with the left hand terminal ofthe winding 17, while the right hand terminal of i5 is connected withthe left hand tenninul of the winding 18. Similarly the left handterminal of the winding 16 is con nected with the right hand terminal ofthe winding 17, and the right hand terminal of 16 is connected with theright hand termizeal of the winding 18.

will, of course, be understood that the terms left and right hand, asused herein are not necessarily expressive of physical.

positions on relations in the actual wind-- ings as used. They derivetheir si ificancefrom the electrical relations expressed by the diagramin Fig. 1, and, as so used, these terms will be readily understood bythose skilled in tl cisrt. lVith this understanding, then it willmo seenthat in the arrange ment illustrated thesecondary windings are found intwo pairs corresponding respectively t0 the two primaries 13 and 14; andthat the left and right terminals of the left hand member of each pairare connected respectively with the left hand terminal of the left handmember and with the left hand terminal of the right hand member of the lThese connections being made, free only the right hand ten band membersof the two and being connectvinolings 16 and 17.

ed, the proper relation of the windings is established. This relation isillustrated in the vector diagram, Fig. These windings supply current tothe four electrodes 19, 20, 21 and 22 suspended movably in a well knownmanner over the bath 23 in the crucible 2%. For the purposes of myinvention these electrodes are connected as follows: Electrode 19 isconnected with the left hand terminals of windings 15 and 17. Electrode22 is connected with theright hand terminals of windings 16 and 18.Electrode 20 is connected with the remaining. terminals of windings 15and 1S; and electrode 21 is connected with the remaining. terminals ofEach electrode is therefore connected with. two' secondary windings. Itwill, of course, be understood that the particular relative positions ofthe four electrodes shown in the drawing are not essential to theinvention. Upon analysis it will be seen that two of the electrodes areconnected to the right and left terminals respectively of the left handmember (15) of one pair of secondary windings. while the other twoelectrodes are similarly connected with the right and left terminalsrespectively of the right hand winding (16) of the same pair. Theconnections of these electrodes with the windings in the other pair ofsecondaries are determined by the permanent inter-connection of thesecondary windings already described.

'By employing the arrangement described,

the current leaving any one of the four electrodes does not returnexclusively through any single electrode. Consequently, if any of thefour approaches the bath too closely or does not approach itcloselyenough, a single ammeter related exclusively to the 1 supply conductorof that electrode will indicate an increase or decrease of currentbetraying the existing diiiiculty. Such an ammeter can then either serveto guide hand control or to govern automatic control in any well knownmanner, without the necessity of using voltmeters.

In Fig. 1 l have indicated. four individual ammeters'25, 26., 27 and 28,shown diagrammatically as suitably related to the feeding conductors ofthe four electrodes.

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necting the terminals of said secondary windings so as to produce adelta connection expressed by a rectangular vector diagram, a crucible,four electrodes over the same, and conductors connecting said electrodesto said secondary windings at the corners of the square in said vectordiagram.

3. In an arcing electric furnace, a two phase transformer having twoprimaries and a pair of secondary windings for each pri- .mary, andconductors inter-connecting said secondary windings so that the left andright terminals of the left hand member of each pair are connectedrespectively with the left hand terminal of the left hand memher andwith theleft hand terminal of the right hand member of the other pair,the remaining free terminals being mutually connected.

4C. In an arcing electric furnace, a two phase transformer having twoprimary.

windings and apair of secondary windings for each primary winding, saidsecondary windings being inter-connected so as to produce a deltaconnection expressed by a rectangular vector diagram; in combinationwith a crucible, and four electrodes over the same, two of saidelectrodes being connected respectively with the right and leftterminals of the left band member of one of said pairs of secondarywindings, while the other two electrodes are connected respectively withthe right and left terminals of the right hand winding of the same pair.

In testimony whereof, I affix my signature. 1

JUSEPH LAWTON DIXON.

topics of this patent may be obtained for five cents each, by addressingthe @ommissioner of Patents, Washington, ll). 43.

